Boyle and Rawlinson's formula is applied to the design of low loss ultrasonic lenses of plastics, metals, and other solids. Plano‐spherical or plano‐cylindrical ultrasonic lenses are used in direct contact with the generating crystal as well and called “ultrasonic contact lenses” in analogy with the corresponding devices for the human eye. To reduce the loss of energy by reflection of ultrasonics at the boundary between two media of different acoustic resistivities plane parallel plates are employed, named “transmission plates.” They are analogs of the coatings used to extinguish reflection of light from glass. The high efficiency of the devices described above is recorded in various ways. The usual optical methods are simplified and improved by the application of the concentrated‐arc lamp. Eventually the possibilities of further developments are discussed and some problems awaiting solution.